US 3272510 A
Description (OCR text may contain errors)
Sept. 13, 1966 J. A. I. OHLUND ETAL. 3,272,510
GENERATOR 0F SIMULATED SMOKE SIGNALS FOR GUNNERY TARGET PRACTICE 4 Sheets-Sheet 1 Filed Nov. 19, 1962 Wu m "mm 7 Ju U 5 n WAR fimhww 95% AR & Q n v M7 1. OHLUND ETAL 3,272,510 GENERATOR OF SIMULATED SMOKE SIGNALS Sept. 13, 1966 FOR GUNNERY TARGET PRACTICE 4 Sheets-Sheet 2 Filed NOV. 19, 1962 Sept. 13, 1966 Filed Nov. 19, 1962 J. A. I. OHLUND ETAL GENERATOR OF SIMULATED SMOKE SIGNALS FOR GUNNERY TARGET PRACTICE 4 Sheets-Sheet 5 ATS .KarZ Ra narAncYarssun 915 m Sept. 13, 1966 Filed Nov. 19 1962 J. A. l. OHLUND ETAL GENERATOR OF SIMULATED SMOKE SIGNALS FOR GUNNERY TARGET PRACTICE 4 Sheets-Sheet 4 SH7L2990W JUZmA lax .Z'ngvar UZ-zZund .K'ar'gljs arAnderssun United States Patent 3,272,510 GENERATOR 0F SIMULATED SMOKE SIGNALS FOR GUNNERY TARGET PRACTICE John Alex Ingvar Ohlund, Huskvarna, and Karl Ragnar Andersson, Jonkoping, Sweden, assignors to Saab Aktiebolag, a corporation of Sweden Filed Nov. 19, 1962, Ser. No. 238-348 5 Claims. (Cl. 273-102.2)
This invention relates to apparatus for gunnery target practice, and refers more particularly to means for generating a visible signal in the nature of a simulated smoke putt to indicate to a gunner engaged in practice shooting at a target that he has placed a shot in a predetermined relationship to the target.
From the standpoint of training efiiciency it is desirable that a gunner shooting at a target be apprised of the results that he has achieved as soon as possible after he has fired each shot and while the circumstances of the firing of the shot are still fresh in his mind. This is especially true in aerial gunnery, in which the gunner must take account of many rapidly changing variables in aiming each shot, but in which firing results can be quickly communicated to the gunner only by radio signals or by visible signals which can be seen from a substantial distance so as to be readily perceptible from the gunners aircraft.
Radio signals are generally unsatisfactory because, among other things, they are somewhat unrealistic in that they do not simulate the conditions that would occur in actual combat firing.
With the foregoing in mind it is a principal object of the present invention to provide apparatus which produces a signal that is visible to the gunner immediately after he has successfully placed a shot in the target and which signal has the appearance of a puff of smoke and is thus readily perceptible at a distance from the target and at the same time affords a realistic simulation of the results that could be expected from successful firing under actual combat conditions.
Another object of this invention is to provide a signalling device of the character described which is particularly well adapted for aerial gunnery target practice, including air-to-air gunnery, in that it comprises means for indicating to an aerial gunner, by a readily perceptible puff of simulated smoke, that he has scored a hit upon a target at which he is shooting, such signal being produced immediately after a projectile strikes the target.
A further object of this invention is to provide simulated smoke generating apparatus of the character described by which a continuous output of simulated smoke can be produced for the purpose of assisting a gunner in locating a target at which he is firing, and by which more intensive puffs of simulated smoke can be released to signify hits on the target, and which can also be employed to simulate return fire from the target.
A more specific object of the present invention is to provide apparatus for gunnery target practice by which a simulated smoke puff is produced to signify each shot that strikes the target, which apparatus comprises transducer means located at the target and which produces an electrical impulse in response to the passage of a missile in a predetermined relationship to the target, and means comprising a solenoid valve and a simulated smoke generator for releasing, through a nozzle outlet located at or near the target, a quantity of powdered material entrained in gas under pressure each time the solenoid valve is opened in response to an electrical impulse from the transducer means.
It is also an object of this invention to provide a simulated smoke generator of the character described which is especially well adapted for cooperation with a target 3,2 72,5 10- Patented Sept. 13, 1966 transducer device of the type described and claimed in the copending application of J. A. I. Ohlund et al., Serial No. 173,636, filed February 16, 1962, for Signalling Device for Scoring Gunnery Target Practice, now Patent Nov 3,158,372.
Another specific object of the present invention is to provide, in a simulated smoke generator of the character described, a container wherein a supply of finely powdered material such as soot or talcum powder is stored in contact with gas under pressure, and means for controlledly releasing such gas from the container with the powdered material entrained in the gas to simulate smoke.
A further specific object of the present invention resides in the provision, in a simulated smoke: generator of the character described, of a container for finely powdered material and gas under pressure, which container can be charged with powdered material by mere insertion of a bag containing such material downwardly into the container and Withdrawal of the empty bag from the container.
The present invention has another of its specific objects the provision of simulated smoke signal generating means for gunnery target practice having electronic means for amplifying the electrical impulse signals produced by a target transducer device of the type hereinabove mentioned, for discriminating against signals from the transducer which are due to causes other than the impacting of a missile against the target, and for producing an output signal having substantial duration as compared with the brief impulse from the transducer means, so that the output of such electronic means can be utilized to efiect discharge of a simulated smoke puff of such duration and magnitude as to be readily visible to a gunner at a substantial distance from the target.
With the above and other objects in view which will appear as the description proceeds, this invention resides in the novel construction, combination and arrangement of parts substantially as hereinafter described and more particularly defined by the appended claims, it being understood that such changes in the precise embodiments of the hereindisclosed invention may be made as come within the scope of the claims.
The accompanying drawings illustrate several complete examples of the physical embodiments of the invention constructed according to the best modes so far devised for the practical application of the principles thereof, and in which:
FIGURE 1 is a more or less diagrammatic perspective view of the apparatus of this invention associated with a target to produce a simulated smoke signal at the target when the target is struck by a projectile;
FIGURE 2 is a perspective view of a powdered material container which comprises a part of the apparatus of this invention, portions of the container being cut away to show details of the interior thereof;
FIGURE 3 is a perspective view, with portions cut away and shown in section, of the solenoid and outlet nozzle of the apparatus illustrated in FIGURE 1;
FIGURE 4 is a circuit diagram of the amplifier and release impulse generator of the apparatus of this in vention;
FIGURE 5 is a more or less diagrammatic view illustrating the application of the apparatus of this invention to a target having the shape of a tank for the purpose of simulating return fire from the target;
FIGURE 6 is another more or less diagrammatic View showing another application of the apparatus of this invention, in this instance for the purpose of producing smoke signals indicative of hits scored upon a portable target having the shape of a tank; and
FIGURE 7 is a more or less diagrammatic View of the application of the apparatus to an airborne target for rendering the target readily visible and for indicating hits on the same scored during gunnery practice firing thereat.
Referring now more particularly to the accompanying drawings, the numeral 5 designates generally a target at which gunnery practice firing can be directed. When a projectile makes a hit on the target, a transducer 6 on the target produces an electrical impulse output which is transmitted, by way of conductors 7, to the simulated smoke generator of this invention, which is generally designated by 8. In response to such impulse the smoke generator discharges a puif of simulated smoke through a nozzle 9 at the target, thus providing a readily visible and very realistic indication that a hit has been scored.
In general the target 5 and the transducer 6 attached thereto correspond to the apparatus disclosed and claimed in the aforesaid Patent No. 3,l5 8,372. Briefly, the target proper comprises a panel 10 of a relatively dense material such as hardboard, suspended on a frame or stand 11 by means of resilient strips 12 of rubber or the like which substantially insulate the panel from vibrations of the frame. The transducer 6 is attached to one corner of the panel and has its axis of sensitivity lying substantially in the plane of the panel and extending toward the central portion thereof so that the transducer is responsive substantially only to shock impulses that travel edgewise through the panel, such as would be caused by a projectile penetrating the panel. The transducer 6 therefore produces an electric-a1 impulse output only in response to an accurately placed shot, and discriminates against near misses as well as vibrations and shock impulses from other sources.
The simulated smoke signal generator 8 of this invention comprises, in general, a sealed container 14 which is adapted to hold a supply of finely powdered material such as soot or talcum powder, a pressure vessel or bottle 15 for holding a supply of compressed air, carbon dioxide, or other inert gas under pressure, and which is normally in constant communication with the interior of the container 14, a solenoid valve 16 which controls discharge of powder entrained in pressurized gas from the interior of the container 14 through the nozzle 9, and an amplifier 17 connected between the transducer 6 and the solenoid valve 16.
As best seen in FIGURE 2, the container 14 is preferably cylindrical and has a large opening 20 in its upper end wall that can be closed by a removable cover 21 which engages under the inner surface of the top wall, around the marginal edge portion of the opening 20. Preferably the opening 20 is elliptical or otherwise noncircular, and the cover has a corresponding shape so as to be readily insertable through the opening although it is larger than the opening. A gasket 22 at the underside of the top wall of the container, all around the opening 20, insures that the cover makes a good seal. The cover is drawn up into compressive engagement with the gasket by means of a cross bar 23 which has its end portions overlying the top of the container and which is secured by a screw 24 threaded into the center of the cover.
To facilitate charging the container with powdered material it is provided with sharp edged knife means 26 projecting upwardly from its bottom wall and which in the present case is shown as four pyramidally arranged sheet metal strips with sharp edges. It is thus possible to pack age the powdered material in standard bags of, e.g., plastic film. As such a bag is inserted downwardly into the con tainer 14 through the opening 20 therein, the knife means 26 cuts open the bottom of the bag so that the bag can be emptied into the container as it is withdrawn therefrom.
Gas is normally maintained under substantially constant pressure in the interior of the container 14, in contact with the powdered material therein, and to this end the inside of the container is communicated, by way of a duct 28 that comprises a manually controllable pressure reducing valve 29, with the compressed gas vessel 15. A
conventional manual valve 30 on the compressed gas bottle 15 permits the same to be out off from the container 14 when the apparatus is not in use or when the bottle is to be changed. The reducing valve 29 insures that the pressure of gas in the container 14 will be maintained at a substantially constant value.
The duct 28 leading from the bottle 15 is connected with an inlet fitting 30 on the container 14 from which an inlet tube 31 extends down into the interior of the container with its month near the bottom thereof. Gas, with powder entrained therein, is expelled from the container through an outlet duct 32 which extends downwardly into the container from an outlet fitting 33 on the top thereof and which terminates at its bottom in a plurality of branches 34 that open to different parts of the bottom portion of the container. The arrangement of the branch ducts 34 permits powdered material to be expelled from the container even when the supply of such material in the container is very low. By means of a manually controllable vent nipple 35 on the top of the container gas can be released from the container without discharge of powder, so that the cover can be removed for recharging of the container.
As best seen in FIGURE 3, the solenoid valve 16 which controls discharge from the container 14 comprises a valve body 36 through which a passage 37 extends from an inlet port 38 at one side of the body to an outlet port 39 at the other side thereof. The inlet port 38 is connected, by means of a duct 40, with the outlet fitting 33 on the container 14, while another duct 41 communicates the outlet port 39 with the discharge nozzle 9. The medial portion of the passage 37 is enlarged to provide a valve chamber 43 which opens to the top of the body 36 and which is closed by a housing 44 that is secured to the top of the body and wherein an annular winding 45 is housed. A substantially tubular sleeve member 46, threaded into the lower portion of the valve chamber, defines a valve seat in the passage 37. The valve element 47 that cooperates with this valve seat is formed on the bottom of a magnetically responsive plunger 48 which is coaxially slidable in the winding 45 and which projects down into the upper portion of the valve chamber. Also housed in the valve chamber is a coiled compression spring 49 that surrounds the lower portion of the plunger and reacts between the underside of the housing 44 and a washer 50 secured on the lower end of the plunger. The spring 49 thus biases the plunger downwardly toward a seated position of the valve element 47 thereon, but it will be apparent that the plunger will be drawn upwardly by magnetic attraction when the solenoid winding 45 is energized by an electric current, thus carrying the valve element 47 off of its seat to permit gas having powder entrained therein to flow out of the container 14 and to the nozzle 9 by way of the ducts and 41 and the passage 37 in the solenoid valve body 36.
To keep powdered material away from the plunger 48, the spring 49 and the winding a diaphragm can be inserted between the lower part of the plunger and the valve body.
Preferably the discharge nozzle 9 has a plurality of outlet orifices 52 therein which open in generally radially outward directions so that the simulated smoke is dispersed over the face of the target in a manner which realistically simulates the impact of a projectile. Obviously the nozzle could be made interchangeable with others that would provide for other patterns of dispersal of the simulated smoke signal. A suitable bracket 53 provides for securement of the nozzle 9 to the target frame 11.
As suggested by FIGURE 5, the solenoid valve could be controlled by a manually operated switch 54, or could be replaced by a manually operated valve element, so that an operator could, in either case, produce the appearance of bursts of smoke simulating return fire from a target on which the discharge nozzle is installed. Also, as suggested by FIGURE 7, a suitable by-pass 91 (see FIGURE 1) around the solenoid valve can be provided whereby a constant but relatively light stream of simulated smoke can be made to emanate from the target to facilitate location and identification of the target, impacts on the target then being signalled by larger outputs of smoke produced in consequence of opening of the solenoid valve for a brief period after each hit is scored.
In the apparatus illustrated in FIGURE 6 the target simulates the appearance of a tank, and the target proper comprises a panel 10' of hardboard or the like in the shape of a tank, secured to a frame or stand 11 by means of resilient mounting elements 12. The nozzle 9 is preferably located near the center of the panel for discharge through the same to the front thereof. As with the embodiment of the invention illustrated in FIGURE 1, simulated smoke is dispersed whenever a hit on the target panel is detected by a transducer 6.
The electrical impulse signal produced by transducer 6 in response to a hit upon the target is both relatively weak and of relatively very brief duration. It is therefore necessary to amplify such signals, to produce currents of sufiicient magnitude to actuate the solenoid valve, and to increase the effective duration of such currents so that the solenoid valve will be held open for a long enough period of time after each hit to produce a simulated smoke puif of sufficient size and density to be readily visible to the gunner. These two functions of amplification and increasing the duration of the solenoid energizing current are performed by the amplifier 17, the circuit of which is diagrammatically illustrated in FIGURE 4.
The conductors 7 that carry the output of the transducer 6 are connected with the opposite ends of a potentiometer 63, which can be adjusted to discriminate against relatively weak signals from the transducer, produced by causes other than a direct hit on the target panel. The wiper of potentiometer 63 is connected with an amplifier-filter circuit comprising a transistor 64 and a resistance-capacitance network consisting of resistors 65, 66, 67 and 68 and capacitors 69, 70, 71 and 72. Capacitors 69 and 71, which determine the low frequency limits of the circuit, are so chosen as to discriminate against frequencies below about 1000 c.p.s., corresponding to noises due to wind sough and the like. Capacitor 70, which determines the upper frequency limit of the amplifier, is of such value as to discriminate against frequencies above 3000 c.p.s., so that the amplifier passes signals within the band of 10004000 c.p.s., containing the frequencies of vibrations of the panel due to hits thereon.
The amplifier-filter circuit thus cooperates with the transducer 6 and potentiometer 63 in rejecting spurious signals due to jerks on the cable of a towed target, bow wave shocks from projectiles passing near the target without striking it, and other causes. The potentiometer 63 also makes it possible to so adjust the apparatus that it will pass only the relatively strong signals caused by impact upon the target of projectiles from large bore weapons, and will reject the weaker signals due to hits from small bore weapons such as rifles. Such adjustment for projectile size is particularly useful where the apparatus is used with a tank target like that illustrated in FIGURE 6.
The output of the amplifier comprising the transistor 64 is fed, through a diode 84, to a monostable flip-flop circuit comprising a pair of transistors 73 and 74, by which the effective duration of the signals from the amplifier is effectively increased so that the solenoid valve is energized for long enough periods to provide readily visible dis-charges from the nozzle. In addition to transistors 73 and 74, the flip-flop circuit comprises resistors 75, 76, 77, 78 and 79, a potentiometer 80, a pair of capacitors 81 and 82, and a pair of diodes 84 and 85. The amplifier and its associated flip-flop circuit are powered by a battery 58 or other D.C. source, connected with the electronic circuit by means of conductors 59. The output terminals of the amplifier unit 6 are connected with the winding 45 of the solenoid valve by means of conductors 57, energization of which is controlled by a switch element 62 actuated by a relay winding 61.
When no signal is received from the transducer, the flip-flop circuit is in a stable condition, in which transistor 74 is conducting current and its collector 740 is at a low potential, e.g., 1.5 v. The value of resistor 76, which is in series with the emitters of the two transistors, is so chosen that the voltage drop across it under these conditions will be about 1.0 v. If the voltage divider formed by resistor 76 is suitably dimensioned, the base 73b of transistor 73 will then be at such potential in relation to the emitter 73e thereof that said transistor will be at cut-off. The relay winding 61 is connected in series with the collector 730 of transistor 73, and hence when transistor 73 is at out off, only a negligible current will flow through relay winding 61, insuflicient to close switch element 62.
If a signal current is now supplied from the amplifier to the base 73b of transistor 73, by way of diode 83, the pre-volta'ge across resistor 76 is neutralized and transistor 73 is rendered conductive, with the result that the potential on its collector 73c decreases. Current then flows through the transistor and the relay winding 61 in series therewith, thus efiecting closure of switch element 6-2 and consequent energization of winding 45 to open the solenoid valve. Such current flow through transistor 73 also charges capacitor 81, which is connected with the collector 730 of transistor 73 in parallel with winding 61. Through its connection with that capacitor, the potential of the base 74b of transistor 74 is decreased to the point where that transistor is rendered non-conductive. The condenser 81 discharges through resistor 78 and potentiometer 80, which are connected in series with it, and hence the duration of the unstable condition, in which current flows in winding 61, depends upon the capacitance of condenser 81 and the combined resistance of circuit components 78 and 80. Preferably the circuit constants are so chosen that potentiometer can be adjusted to provide a duration of 0.5 to 1.5 seconds for target practice signalling work, and to provide longer intervals in cases where the apparatus is used to simulate return fire from a tar-get or the like.
Diode 74 is connected across relay winding 61 and diode 85 is connected across the switch element 62 to prevent detrimental voltage peaks that might develop upon disconnection of the inductive loads presented by the relay and the solenoid valve.
From the foregoing description taken together with the accompanying drawings it will be apparent that this invention provides means for producing a visible signal, in the nature of a simulated smoke putt, for indicating to a gunner engaged in target practice that he has scored a hit on the target. It will also be apparent that the apparatus of this invention is capable of producing such a signal immediately after the hit is scored, and can also be employed to produce simulated smoke puffs and clouds for other purposes such as providing a smoke trace that assists a gunner in locating a target and producing an appearance of return fire from a target.
What is claimed as our invention is:
1. Apparatus for providing to a gunner at a distance from a target a visual indication that he has scored a hit upon the target, in the form of a simulated smoke signal produced immediately after the target is hit, said apparatus comprising:
(A) a container adapted to hold a supply of finely powdered material in contact with gas under pressure and having (1) a gas-tight closure, (2) an outlet near its bottom and (3) an inlet for gas under pressure;
(B) means for connecting said inlet with a source of gas under substantially constant pressure;
(C) a solenoid valve having inlet and outlet ports;
(D) duct means connecting the outlet of the container with the inlet port of the solenoid valve so that the valve can control release from the container of powdered material entrained in gas under pressure;
(E) nozzle means located at the target and connected with the outlet of the solenoid valve, through which gas and entrained powdered material are expelled into the air when the valve is open, to produce the appearance of smoke;
(F) transducer means at the target for producing an electrical impulse in consequence of passage of a projectile in a predetermined relationship to the target; and
(G) amplifier means having (1) input terminals connected with the transducer means and (2) output terminals connected with the solenoid valve, said amplifier means comprising time delay holding means for delivering a current at relatively long duration to said output terminals, to open the solenoid valve for a sufficient time to produce a distinctly visible simulated smoke pufi' in response to the brief electrical impulse delivered to said input terminals from the transducer means.
2. The apparatus of claim 1, further characterized by the fact that said outlet comprises a plurality of branch tubes, each having one end connected to an outlet duct which is common to the several branch tubes, the other ends of the several branch tubes being in different locations near the bot-torn of the container to insure that powdered material will be entrained in gas released from the container even when only a small amount of powdered material is present in the container.
3. The apparatus of claim 1, further characterized by the fact that said amplifier comprises: an amplifier having a resistance capacitance filter network for amplifying impulse signals within a range Off frequencies corresponding to those caused by the impact of a projectile upon the target and for rejecting signals of other frequencies. Y
4. The apparatus of claim 1 wherein said gas tight closure for the container comprises a removable top thereof, further characterized by: knife means in the bottom of the container having an upwardly projecting cut-ting edge by which the bottom of a bag filled with powdered material can be cut in consequence of downward insertion of the bag into the container, to thus effect release of the powdered material into the container upon withdrawal of the bag from the container.
5. The apparatus of claim 1, further characterized by: duct means for connecting the outlet of the container to the nozzle means in by-pass relation to the solenoid valve to provide for the emission of a constant but relatively light stream of simulated smoke.
References Cited by the Examiner UNITED STATES PATENTS 609,970 8/1898 Lochmann 222399 1,287,767 12/1918 Schanschieif 469 2,148,438 2/1939 Crain et a1 273-102.1 2,608,025 8/1952 Miller 469 2,788,607 4/1957 Ward 469 2,932,126 4/1960 Howell 469 X 3,022,076 2/1962 Zito 273102.2
FOREIGN PATENTS 552,189 1/1923 France.
DELBERT B. LOWE, Primary Examiner.
RICHARD C. PINKHAM, Examiner.